That plan worked great for the cell phone, where £10 or €15 paid for more than enough service in each country -- but the iPad was a different story. The United Kingdom has four carriers that offer iPad 3G service, with 1GB of usage for just £10, but all had the same rule: You had to have the 3G SIM sent to a U.K. mailing address, even for pay-as-you-go use. (By contrast, for phones, including iPhones, you can walk into any store and pick up the SIM right there.) Anyhow, the timing didn't work out, given we were at no one's home for more than a couple days. We could've had the SIM sent to someone's home a few days out, but that meant the number of days we'd actually have it wasn't worthwhile.
I lived without 3G in England, but I had subscribed to a Boingo mobile-device Wi-Fi roaming account for $8, hoping to take advantage of the ubiquity of Wi-Fi hotspots in Europe. There were hotspots nearly everywhere, but Boingo didn't have relationships with most of them. As a result, I was pretty much without Wi-Fi in England, except at a few relatives' homes.
In France and Belgium, the 3G charges are much higher -- even more expensive than in the United States, which is already among the highest in the world. Fortunately, most places we stayed had Wi-Fi included. (Boingo again proved to be a disappointment, but there were enough free hotspots to make up for its lack of relationships.) Signing up for iPad 3G service in France and Belgium is also pretty convoluted, even if you speak the language as I do. I didn't bother trying.
Non-AT&T 3G in the United States for an iPad
Despite my complaints about the hassles of getting 3G iPad service in those three countries, at least there were options to get 3G service for my iPad in Europe. Travelers to the United States can't get a pay-as-you-go iPad 3G SIM from the sole carrier here, AT&T.
One option for such travelers (as well as for U.S. residents who don't want AT&T service) is to use a Novatel MiFi device from a U.S. pay-as-you-go provider such as Verizon Wireless or Sprint's Virgin Mobile subsidiary. The MiFi accesses the 3G network and connects the iPad or any device to it over a Wi-Fi pass-along connection. Verizon's no-commitment pricing is attractive: $20 per 1GB of usage, though only on iPads. (Its rates jump significantly if you also want to connect other types of devices.) As you'll soon see, the Virgin calculation makes for a tougher call.
If you choose the MiFi route, you have another box to carry, but that's not a terrible burden for periodic on-the-go use. However, as several friends have discovered, the MiFi's battery life is just 2 or 3 hours. The iPad runs 10 to 11 hours in my usage, even with 3G on all day. You really can't use the MiFi-iPad combination to be online all day, as you can the iPad Wi-Fi + 3G model.
MiFi as an iPad's 3G conduit is not all that viable -- whether you're a visitor to the United States or a U.S. resident looking to avoid AT&T.
3G when you need more than an iPad
I'm amazed how much work I can with an iPad. In a few years, I think most people will have replaced laptops with iPads or similar slates, relegating today's Windows PCs and Macs to workstations used for resource-intensive applications such as company budgeting, advanced analytics, page layout, video editing, and photo manipulation. We'll all have PCs on the desk, but we'll carry slates with us when on the go.